Sunday, May 11, 2014

Real World Range Test: BMW i3 vs BMW ActiveE


Now that BMW has begun to deliver some BEV i3s to the ActiveE Electronauts, some of those in the ActiveE trial lease program who haven't yet gotten their i3 have been asking how the i3 compares to the ActiveE. Questions on ride quality, acceleration, handling and charge rate have been asked, but the biggest concern is: How does the range compare? After all, with electric vehicles, range is paramount.

So I got together with Michael and Pamela Thwaite who just last week picked up their Ionic Silver i3 and we mapped out an 80 mile loop that would include roughly 50% highway and 50% secondary and tertiary roads. While everybody has different driving needs and patterns, it was our hope that this course would provide an evenly balanced mix of different driving conditions. That being said, this wasn't a carefully controlled scientific experiment. We didn't weigh ourselves to make sure both vehicles were carrying the same weight, we didn't calibrate our speedometers or record the barometric pressure so please don't bother commenting on why this was a flawed experiment because it wasn't perfectly controlled. We did make sure we had proper tire pressure, we took turns following and leading each other and we tried our best to maintain the same constant speeds. We drove in the default (Comfort Mode) driving mode and didn't use Eco Pro driving mode at all. We met on Saturday morning at my restaurant which has two ChargePoint EVSEs in the parking lot and after about two hours of charging we set out with Pamela driving their i3 and my wife, Meredith, driving my ActiveE. Michael and I were the co-pilots so we could live blog the event, post pictures on social media sites and make sure we stayed on course.
Both cars charging up for the challenge at my restaurant in Montclair, NJ.



With both cars fully charged, the ActiveE showed an estimated 86 miles of range, while the i3 predicted 98. Which will be more accurate?

It was a warm, cloudy day with temperatures in the 80's. We knew we would need the air conditioning so we agreed to both use it only when we were driving over 45mph and under that we would just open the windows. The first stop, about 20 miles in, was the headquarters of BMW of North America. We figured it was an appropriate destination and since it was a Saturday they wouldn't mind us parking in front of the main entrance for a photo op. We were pleased to find a life sized i3 decal applied to the glass of the front doors. BMW is evidently proud of their first all electric vehicle. At this point we had both used 19% of the available battery. I was surprised the i3 was holding its own, especially since that leg was about 75% highway. We did drive the speed limit on the Garden State Parkway though, and stuck to about 60mph. I'm sure if we drove faster the i3 would have used more battery than the ActiveE. Still, I really expected the ActiveE to jump out to an early lead since we were driving at highway speeds for most of the first leg.



At BMW HQ in Woodcliff Lake NJ - Note the i3 overlay on the doors
The next leg of the journey would be about 40 miles, with the first 30 miles or so on all secondary and tertiary roads and we would end up in Denville, NJ. Michael and I were trading texts during the way and for at least the first 20 to 25 miles of this leg (a total of 40 to 45 miles driven) we were still nearly dead even in battery state of charge with the ActiveE having a 1% advantage with battery state of charge.  On route to the Route 80 leg (which would be our highest speeds of the day and all uphill) we were driving on Route 23 at 50 to 55mph and the ActiveE started to gain an advantage of a few more percent.


Driving the back roads of Bergen county was a pleasure on a nice sunny Spring day



















We took turns following and leading each other for the entire route.


Then came the blow that the i3 couldn't recover from. Driving on Route 80 upgrade at the 65 miles an hour speed limit for about 10 miles finally gave us the separation we expected. We were 60 miles in (59.8 exactly) and the ActiveE now had a 6% state of charge lead (46% to 40%) and a predicted range of 9 more miles (40 miles to 31 miles). This clearly reinforces what many of us imagined. The i3 is a warrior on low speed driving, but at faster highway speeds it's a bit out of its element and the range will be substantially compromised.  At highway speeds the weight of the car isn't nearly as important as its aerodynamics, the exact opposite of low speed driving where weight influences energy use much more. The lightweight i3 has a respectable Cd of .29, but it is tall and has a large frontal area which increases its CdA (the combination of drag coefficient and frontal drag area) making it less than ideal for cheating the wind resistance at highway speeds.









The final 20 miles were about 30% highway (this time down hill most of the way) and 70% secondary roads with about 4 miles of stop and go, traffic light to traffic light driving. We decided to make one last stop at an appropriate destination which happened to be along the way. We stopped at the Thomas Edison National Historic Park in West Orange. What would be more appropriate for an electric car challenge anyway?


After the quick stop we headed back to Nauna's and finished the day driving exactly 80 miles. The ActiveE won the range challenge by 6 miles. Here are the final statics:

2011 BMW ActiveE
Remaining SOC: 27%
Estimated miles remaining: 22
Trip efficiency: 4.1 miles per kWh
Total miles: 102

2014 BMW i3
Remaining SOC: 20%
Estimated miles remaining: 16
Trip efficiency: 5.4 miles per kWh
Total miles: 96




So adding the mileage driven to the remaining mileage the i3 ended up with 96 miles of range and the ActiveE with 102. The i3 actually came very close to predicting the actual range and was only off by 2 miles since it predicted 98 miles of range when it was fully charged that morning. My ActiveE actually beat its range prediction by 16 miles, but that is because my regular driving routing is mostly highway so the car has learned to predict the range based primarily on high speed highway driving. All in all the i3 fared about as well as I expected. It is an incredibly efficient electric vehicle and is in fact now the most efficient car sold in America. However the ActiveE has a battery that is nearly 50% larger (21.6kWh's to 32 kWh's) than the i3's battery and in the end battery size beat efficiency. If the i3 had just a couple more kWh's, I'd be writing a different ending. BMW has been billing the i3 as its "Megacity" car. That was even the codename during development and they weren't kidding. It is much better suited to live its life on congested city streets than it is roaming the high speed highways of the US and the Autobahns of its homeland. I would speculate the i3 will only go about 70 miles if driven all highway, and that's at the 65 mile speed limit. If you were to increase that to 70 or 75 miles than the range will likely drop to 60 to 65 miles. However if you were to drive on secondary roads at around 35 to 40mph, I suspect 100 to 110 miles would be easily attainable in moderate temperatures when you don't need the air conditioning or heater much. So if I were rating the range of the all electric BMW i3, I'd say 60 to 110 miles, conditions provided.

The Thwaite's i3 topping off after the range challenge
One last no-so-small detail. The i3 we used is brand new, while my ActiveE is 28 months old and has 20,100 miles on it. Based on my recorded data I believe its battery has lost between 8% and 9% capacity. If you factor that in, it's clear that while my two year old ActiveE has a slightly better range than a new i3, it had a substantially better range when it was new. Probably about 15% more, which actually coincides with the EPA range ratings for both vehicles.



Some more pictures of the day:


36 comments:

  1. Thank You for this comparison. As my driving pattern involves quite a few miles nowadays at 75 mph or so, the i3 most likely would have proven a challenge and I would have to be thinking REX. While I love what BMW has created with the i3 and the i brand, your test and what I'm reading from others reaffirms we made the right choice for the time being by going with a longer range BEV which indeed is less efficient but still allows us to keep our personalized plate: KNOW GAS. :)

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    1. Knowing your driving needs I suspect you are correct and the BEV i3 wouldn't be adequate for you Todd, especially since to do so much highway driving. You would indeed have to have gone for the REx, and we still don't know if the green stickers will be made available as the bill to add an additional 45,000 HOV green stickers is still in the Senate for vote.

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  2. Great to see this thoughtfully executed side-by-side test! It should put a few questions to rest. Many thanks to everyone who has helped to make it happen.

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    1. Thank you George. This probably mirrors your assumptions, no?

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    2. Yes, it does! I think the results mirror my expectations nearly exactly. It looks like you might have selected a fairly representative mix of driving speeds and conditions. Great job! It's pretty amazing that it reflects the results of the new 5-cycle EPA test so well.

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  3. Thank you, Tom and Michael! Very neatly done, and very helpful to people trying to figure out what vehicle will work for them.

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    1. Thanks Chad. Our main goal was to really give an accurate estimation of what kind of range to expect with the BEV i3 under a mix of different driving conditions. Of course YMMV

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    2. Thanks for posting this.
      So is it fair to say that if the non-Rex gets 60-110 miles of range, the Rex, on battery alone, will be about 50-100 miles on battery alone (before REx?). Figure you lose 6% because the Rex kicks in at that SOC, and the car is about 10% heavier, and haven't factored in the loss of heat pump...

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  4. I have to say, looking at both cars side by side the ActiveE looks so much better imho. I started to become accustomed to the "interesting" design (especially the front) of the i3 but this comparison flipped me over again [in favor of traditional exterior design]. I am also kinda baffled that the ActiveE has better range results in the end. I do acknowledge that the test wasn't scientific, but would that make the ActiveE the better EV? Better design (which lies in the eye of the beholder) and better range are huge points when it comes to EVs?!
    Why would BMW build an EV that can be outperformed by its concept/test-run predecessors? I expected the i3 to outrun the AE due to its lightweight construction and "final"-design by far.

    I have to say I am intruiged by this comparison of yours. Didn't expect that at all.

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    1. I totally agree with you, Luke. I think the design of the ActiveE fits American appetites more than the i3, by far. I feel they should have made it shorter (height-wise), more aerodynamic, not a hatchback, and longer. Not quite as big as a Model S, but more like a unique-looking 3-series. Then increase the battery size by 50%, at least, widen the tires, and charge $55k base price. I'm still getting the i3 BEV, but it sucks that, living in LA, I'm going to have to conquer large distances with even less range. Lame-o. BMW should have consulted Americans for an American EV, rather than going with a metro car that is probably better suited for Europeans.

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    2. I had the same impression. I had sort of talked myself into thinking the i3 design was funky, but OK... and then went to the Dallas auto show and saw the i3 next to a sea of beautiful cars...heck next to the rest of the BMW Line-up! Ugh, she, um...well, she has a nice personality! Even now, I wonder if the i3 is selling based on a classic car feature: the acceleration. I am fully convinced the Tesla sales are directly tied to the awesome acceleration. What else really separates the i3 from a Leaf in a meaningful way?

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  5. I think that we're going to have to write down the exact route Tom. We have a benchmark that mirrors the EPA tests, we just need to lock in the weather.

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  6. on the spanish bmw configurator there is an option by mistake for a bigger battery on the i3. maybe thats an indicator that there is something in the works as an option. i was also told by bmw that they work on the option to exchange battery to a bigger one in the future. so maybe we should consider i3 bev over the rex because we couls save the money for bigger battery in the future.

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  7. 5.4 miles per kwh in the i3 is amazingly efficient!
    great job to all.

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  8. Unless I missed it could you let us know what mode the i3 was in while driving?

    Thanks!

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    1. Both cars were driving in the "normal" mode that they defaults to. We didn't use Eco Pro at all.

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    2. So the only explanation left for the range disparity is that the incandescent daytime running lights on the Active E are more efficient than the LEDs on the i3...

      And on that bombshell it is time to end, goodnight! ;)

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    3. Any chance the i3 could run through the route again with Eco Pro, I know it wouldn't be apples to apples but would be interesting to see.

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  9. I have 36k miles on the Active E and am returning it to the dealer this weekend because our i3 has arrived. Am starting to have separation and range anxiety LOL - I love the the Active E so much that I drive it whenever I can and sometimes come home with only 3-5 miles left on the battery. I do a lot of freeway driving in SoCal during my commute. Will be interesting to see what the difference in range will be for me. Will be disappointed if the i3 range is noticeably shorter.

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    1. I do believe it will be especially if you do a lot of highway driving. The EPA range rating for the ActiveE was 94 miles per charge and the same rating for the i3 is 81 Miles per charge. That's pretty much all the proof you need. I'd expect about 15% less range with the i3 in most conditions except low speed city driving. In that case the i3 will likely have an even greater range than the ActiveE

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    2. Absolutely, I totally agree with Tom. It would be best to adjust expectations. The good news is that the i3 gains range back much faster, perhaps at twice the speed of the ActiveE. That's because of its amazing efficiency and faster charging speed. Additionally, the i3 supports SAE combo DC fast charging, which could turn out to be a great option, as soon as more of these stations are installed.

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    3. Thanks for the feedback. There is some freeway, some traffic, some hills, some city. I guess I'll find out next week! Fingers crossed that I can do roundtrip commute (approx 70-75 miles) on one charge. It was no sweat for the Active E - I usually had about 20 miles left when I got home when I didn't run any errands. I guess I'll have to play with it to see how efficient the different EcoPro modes make it, etc.

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  10. Tom
    is the i3 availability limited? If so, when will it be available nationwide?

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    1. It's available nationwide now. The only thing is they are backed up for a few months so of you order one now you most likely won't get it until August sometime.

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    2. Not in Toronto. They are available now. Seems like some buyers cancelled their orders
      I hope the i3 sells well. Although it doesn't appear that way yet.
      I went to a test drive event and I was the only one there

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  11. You need to do the test more than once and switching the driver to to have a average data! ;)

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  13. Well done Tom and Co - good comparison! Folk just need to see the effect of CdA on real world highway driving! And that includes those who wish for less skinny tyres or SUV sized EVs!

    The i3 REX (and BEVs with larger option wheels) have wider 5.5J wheels and 175 profile tyres at the rear so Cd gets worse to a 1990s Toymota Camry 0.30. The proof that the i3 is for slow speed range is also in the Norwegian Race test between Leaf, i3 and VW eUP! : http://www.youtube.com/watch?v=GkU5OjMw0Os

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    1. Good point. Also remember that the REx range on battery alone will be 10-17% worse (there's a thread about this on the i3 forum).
      So expect 50-100 miles of electric range for the REx

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  14. Tom, any sense from your activeE experience how cold weather will reduce range for the BEV (with its heat pump)?
    By cold I mean 0F! Would you guess a 30% reduction in range?

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  15. My i3 is 5 days old and yesterday I took it down to 3 miles remaining, I had driven 79 miles from a full charge - all on EcoPro with 50/50 Hwy/City no AC ... so the mileage is definitely lower than what you were able to get (how??) ... it is a fun Toy and if you view it as exactly that - an expensive fun Toy - you are good !

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    1. We were driving very efficiently and didn't exceed the speed limits. I don't expect to average 90+ miles per charge under normal conditions but you can do it with a light foot and maximizing the regen as much as possible.

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  16. Just as a quick update on a single charge I drove EcoPro for 91.7 miles over a couple days and had 15% SOC left ... so this puppy can get to 105+ miles on one charge if you really need it that day !!

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  17. That's great to hear Pawan, thanks for reporting in.

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  18. I have an i3 in Los Angeles.
    Fully charged I drove to an airport and back. At night with seat heaters.
    I tired to max out the acceleration and speed at every point I could.
    Average speed was 80 MPH; for the most time I drove 95.
    I got 56.8 miles range with a fully charged and unconditioned vehicle

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    1. Really? How did you manage to drive 95mph most of the time when the car speed is limited to 93mph?

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